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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Toxicity to algae data are available for 2 streams within this Category. The ErL50 growth rate range was 2.3 mg/L at 72 hours and 2.1 – 2.2 mg/L at 96 hours. A 72 and 96 hour NOELR of 0.18 mg/L was cited.

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
2.1 mg/L
EC10, LC10 or NOEC for freshwater algae:
0.18 mg/L

Additional information

CAS No 68513-69-9: This study is GLP compliant and follows a standard guideline. It is considered reliable and acceptable for use as a key study. Based on measured concentrations, the EC50 was 2 mg/L at 72 hours and 1.8 mg/L at 96 hours for growth rate, and 1.3 mg/L at 72 and 96 hours for biomass. Based on actual loading rates, the EL50 was 2.3 mg/L at 72 hours and 2.1 mg/L at 96 hours for growth rate, and 1.5 mg/L at 72 hours and 1.4 mg/L at 96 hours for biomass.

CAS No 68513-69-9 and 68921-67-5: This is a GLP compliant, guideline study considered adequate for assessment. After 72 and 96 hours of exposure to Pyrolysis C10+ Fuel Oil (from Pyrolysis Gasoline Distillation) the following conclusions were made. Based on actual loading rates, effects on growth rate (r) gave an EL50 of 2.3 mg/L at 72 hours and 2.2 mg/L at 96 hours and effects on biomass (b) gave an EbL50 of 1.3 mg/L at 72 hours and 1.2 mg/L at 96 hours. Based on measured concentrations, effects on growth rate (r) gave an ErC50 of 1.7 mg/L at 72 hours and an ErC50 of 1.6 mg/L at 96 hours and effects on biomass (b) gave an EbC50 of 0.95 mg/L at 72 hours and an EbC50 of 0.91 mg/L at 96 hours. Effects based on average specific growth rate and area under the growth curves gave a 72 and 96 hour NOELR of 0.18 mg/L and a NOEC 0.12 mg/L.

 

Although measured concentrations were reported as the test substance is a hydrocarbon stream with various components reporting a measured concentration does not relate to a concentration of the raw stream. The results reported as WAF which better represent the potential toxicity of the test substance have been used instead.